What is the author's tone in the novel, Unbecoming?

The novel consists of dialogue and narrative, and some of this has a modern-day tone. For example, there are text messages between Katie and several other characters. These are shortened and abbreviated words, typical of texts, such as “PLSE CME HME” (301) seen in the text Katie sends Caroline after their argument. The font and content are meant to show these are text messages.